Vapor-rectifier.



S. W. FARNSWORTH.

VAPOR RECTIFIER.

APPLICATION FILED OCT. 31. I914.

Patented Nov; 26, 1918.

INVENTOR I dn'gy W. Frnaworih.

ATTORNEY a careful study SIDNEY W. FARNSWORTH, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WESTING- HOUSE ELECTRIC AND MANUFACTURIN VANIA.

e COMPANY, A

conronzl'rrou or PENNSYL- VAPOR-RECTIFIER.

Specification of Letters Patent.

Patented Nov. 26, 1918.

Application filed October 31, 1914. Serial No. 869,528.

To all whom it may concern:

Be it known that I, SIDNEY W. FARNS- WORTH, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement n Vapor-Rectifiers, of which the following is a specification.

My invention relates to vacuum vapor electric apparatus, such, for example, as mercury vapor lamps and rectifiers, and it has for its object to provide means whereby quiet, eflicient and stable operation may be secured, in apparatus of the character specified, by the control of the relative temperatures of the electrodes.

In the operation of vapor rectifiers, especially of the heavy-current, metal-container type, it has been customary practice to artifically cool both the anodes and the cathodes. I have found, however, that it is possible to carry this action too far and to obtain such low temperatures, especially in the anodes, as to seriously interfere with the proper action of the rectifier. I have made of the optimum temperature of both the anode and the cathode in order to secure maximum stability in the rectifying arc and, at the same time, maximum efficiency in operation and have embodied the results of my investigation in the hereinafter described apparatus.

The single figure of the accompanying drawing is a side View, partially in elevation and partially in section, of a rectifier arranged to illustrate my invention.

A tank 1 of the usual construction is provided with suitable anodes 2, a cathode 3 and arc-maintaining means 4. Current is supplied to the anodes by suitable conductors 7 and 8 and removed from the cathode bya conductor 9. The 3 may be controlled in temperature by the circulation of a cooling medium through an annular space between the wall and a 1ack'et 5 surrounding the same. In like manner, the temperature of the anodes may be maintained by forcing cooling fluid through suitable pipes 6 projecting into the hollow interiors thereof and allowing said cooling fluid to escape through annular spaces between the pipes 6 and the walls of the anodes. The cathode and anode cooling systems may be entirely independent, if desired, and each may be provided with any tank 1 and the cathode.

desired means for controllin the temperature of the cooling medium t erein.

The arcing surface of the anodes of a rectifier should be maintained at a temperature above the boiling point of mercury, at the vacuum at which the rectifier is operating, in order to prevent the condensation of mercury vapor thereupon, with resultant destruction of the negative reluctance of the anode and consequent short circuiting of the rectifier or of the rectifier system. On the other hand, the temperature of the anodes should be maintained at a reasonably low figure in order to prevent the warping and destruction of the metal therein and in order to prevent the release of occluded gases. As the result of a long series of tests, I have found that the temperature of the anodecooling medium should be maintained between 80 C. and 100 C.

The cathode, composed of an arcing liquid, such as mercury, should be maintained well'below the boiling point of the liquid in order to prevent excessive vaporization thereof, in order to render the are stable and in order to maintain a low pressure within the container, with attendant low arc losses. Furthermore, I have found that, by suitable adjustment of the difference in temperature between the anodes and the cathode, the efliciency of the rectifier may be varied somewhat. Maximum efficiency appears to be obtained when the anodes are substantially 30 C. higher in temperature than the cathode. a desirable figure for cathode operation being found in the neighborhood of 50 C. A temperature such. as 50 C. is furthermore preferable for the cathode rather than the lower figures which have hitherto been common practice because of the fact that the cathode may be cooled by a much smaller amount of cooling medium, in accordance with the well known thermodynamic law that the rate of heat transfer between two bodies varies directly as the difference of temperature therebetween. This saving in the volume of cooling medium is of great value where it is desirable to save weight, as in electric locomotive practice.

While I have prescribed certain definite figures particularly adapted for the operation of mercury vapor rectifiers, I desire to have it understood that they are more or less approximate in character and vary in by the broad amount with changes in the design of the rectifier or in the composition of the cathode liquid. I therefore do not desire to be held strictly to the figures set forth but wish the limitations of my invention to be set rather and general principles hereinbefore enunciated; a

I claim as my invention:

1. The method of operating a vapor converter embodying a mercury cathode and a solid anode and operating with a vacuum of less than .002 mm. of mercury which comprises passing load current therethrough and maintaining, said anode at a temperature of from 80 to 100 C.

2. The method of operating a vapor converter embodying a mercury, cathode and a solid anode and operating with a vacuum of less than .002 mm. of mercury which comprises passing load current therethrough and maintaining said cathode at a temperature of from to C.

3. The method of verter embodying a mercury cathode and a solid anode and operating with a vacuum of less than .002 mm. of mercury which comoperating a vapor conaces load current therethrough and maintaining said anode at a temperature of substantially C.

4. The method of operating a vapor converter embodying a mercury cathode anda solid anode and operating with a vacuum of less than .002 mm. of mercury which comprises passing load current therethrough and maintaining said cathode at a temperature of substantially 50 C.

5. .The method of operating a vapor converter embodying a mercurycathode and a solid anode and operating with a vacuum of less than '.002 mm. of mercury which comprises passing load current therethroughand maintaining said anode at a temperature substantially 30 C. higher than that of said cathode. r i

In testimony whereof, I have hereunto subscribed my name this 14th day of Oct, 1914:. I

prises passing SIDNEY W. FARNSWORTH.

Witnesses: i

DAVID E. CARPENTER, B. B. Hmns. 

